1. Field of the Invention
The present invention relates to a magnetic rotator designed for use with a stirrer or agitator for externally rotating the member to be rotated which is placed in a container, while the container is sealed.
2. Statement of the Prior Art
In general, a device for rotating the member to be rotated in a container has its rotating shaft passed through, for instance, the bottom face of the container and rotated from the outside of the container by means of a driving unit such as a motor. To keep airtightness between the container and the rotating shaft, some means such as packing and liquid sealing have been used (Japanese Utility Model Laid-Open No. 56-63161).
Such a conventional rotator has had difficulty in keeping a high degree of airtightness because of its rotating shaft passing through a wall face of a container and, moreover, has offered a problem that, when it rotates at a high speed, the degree of vacuum in the container drops due to the heat of friction generated on its sealed portion.